Various fields of use require the use of sterilized polyolefin-based clothing, equipment and tools. For example, it is well known that the operating environments of medical personnel, dental personnel, chemical research personnel, biotech personnel, and other like areas utilize polyolefin-based products that have been sterilized prior to use.
Currently, ethylene oxide has been used to sterilize polyolefin-based products such as medical fabrics that are used as surgical gowns and drapes. However, the potentially hazardous nature and high cost of ethylene oxide sterilization have caused the medical community to consider different sterilization methods. One effective method of sterilization has been the use of gamma irradiation. Although sterilization by gamma irradiation of polyolefin-based products and equipment has been successful, there remain at least two very undesirable side effects caused by the irradiation process. The first undesirable side effect has been a resulting odor that is so extreme that it renders the gamma irradiated polyolefin-based product undesirable for many uses. The second undesirable side effect has been a noticeably decreased strength of the irradiated polyolefin-based products. In fact, the irradiation process has been known to decrease a polyolefin-based product's tear strength by as much as 65% of its non-irradiated tear strength.
It has been shown that the cause for the undesirable odor and the loss in polyolefin-based product strength is a free radical process that occurs when the polyolefins of the product are exposed to gamma radiation in the presence of oxygen. In polyolefin-based products, this process essentially breaks chemical bonds that hold a polyolefin chain together and creates free radicals. This breaking of the polyolefin backbone causes the polyolefin to lose strength proportional to the radiation dosage. The formed radicals are able to recombine with the oxygen in the air, producing short chain acids, oxygenated compounds, such that they become trapped in the product. Butyric acid, one of the acids formed, is a primary suspect in causing the odor.
Although earlier efforts and attempts to eliminate these two undesirable side effects include methods that marginally reduce the odor associated with the gamma irradiation of polyolefin-based products, none has adequately reduced the odor or minimized the reduction in tear strength resulting from the irradiation treatment.
A need therefore exists for a product and method for further minimizing or eliminating the odor that is associated with the gamma irradiation of polyolefin-based products.
Another need exists for a product and method that not only reduces the odor, but also minimizes any decrease in the strength of the polyolefin-based product that is due to the gamma irradiation.